Tier 4 — mechanistic

Discoveries of nicotinamide riboside as a nutrient and conserved NRK genes establish a Preiss-Handler independent route to NAD+ in fungi and humans

Bieganowski P, Brenner C

Cell 2004 117; 4; 495-502

Bibliography

PubMed: PMID 15137942
DOI: 10.1016/s0092-8674(04)00416-7
Funding: Indexed grant support includes NCI NIH HHS. The complete funding declaration is not specified in the accessible abstract.
Competing interests: A complete competing-interest declaration is not specified in the accessible publication information.

Design	In vitro or biochemical mechanistic study
Model	Yeast, human enzymes and food analysis
Sample	Yeast, human enzymes and nutrient-identification experiments
Intervention	NR exposure and NR kinase pathway experiments
Duration	Laboratory experiments with assay-specific time courses
Endpoints	NAD+ pathway or cellular-function measures

The work identified NR as an NAD+ precursor and characterized the conserved NR kinase pathway, including identification of NR in milk.

The work identified NR as an NAD+ precursor and characterized the conserved NR kinase pathway, including identification of NR in milk.

Foundational biochemical evidence, not a human oral-supplement trial.

Editorial review

Last verified 22 October 2026